Vitamin b6 intermediates



Patented June 17, 1947 UNITED STATES I PATENT OFFICE VITAMIN B6 INTERMEDIATES Stanton A. Harris, Westfield, N. J., assignor to Merck & Co., Inc., Rahway, N. J a corporation of New Jersey No Drawing. Application July 28, 1944, Serial No. 547,104

I This application relates generally to a process for the preparation of novel chemical compounds; in a particular sense it is concerned with the preparation of intermediates useful in the synthesis of vitamin B6 (3hydroxy-4,5-di(hydroxymethyl) -2-methyl-pyridine) This application is a continuation-in-part of the copending application by the same inventor, Serial No. 428,080 filed January 24, 1942, which is a division of Serial No. 293,131 filed September 1, 1939, issued February 10, 1942, as Patent No. 2,272,198.

The compounds forming the subject'matter of the present invention are represented by the formula:

wherein X is hydroxyl or a halogen, and salts thereof. I

According to one embodiment of the present invention, a compound of the above formula wherein X is hydroxyl, namely 2-methyl-3-amino-4- 18 Claims. (CL. 260-296) hydroxymethyl-B-aminornethylpyridine, is obtained by hydrolysis of compounds of the formula:

OHQOR HgN CHzNHa accordance with the present invention by treating, preferably with a concentrated hydrohalic acid solution, a compound of the formula:

CHaOR wherein R, is as above, to form the hydrohalide salt which is then converted to the free base by usual operations.

The following examples illustrate methods of carryingout the-present invention but it is to be understood that these examples are given by way of illustration and not of limitation.

Example I orraooam onion HZN GH NH Hm CHzNHz dilHOl H3O h .21101 HaC .2HCl

About 2.24 g. of 2-rnethyl-3-amino-4-ethoxy- Inethyl-5'-aminomethylpyridine dihydrochloride is added to 34 cc. of hydrochloric acid (2.5N) and heated at 1'75-180 C. for about four hours. The solution is then treated with activated carbon, filtered, and concentrated to dryness under reduced pressure. The residue containing the dihydrochloride of 2-methyl-3-amino-4-hydroxymethyl-5-aminomethylpyridine' (M. P. 235-237 C.) is purified by recrystallization from Water and alcohol.

In like manner, 2-methyl-3-amino-4-benzyloxymethyl-5-aminomethylpyridine and Z-methyl-3-amino-4-phenoxymethyl-5-amino methyl pyridine can be hydrolyzed to obtain 2-methyl-3- amino-4-hydroxymethyl-5-aminomethylpyridine.

Example II OHzOH with activated carbon and with silver chloride and then filtered. The filtrate is concentrated under diminished pressure to incipient crystallization, and the product allowed to crystallize. j

The product is removed and'puflfied by known methods to obtain 2-methyl-3-amino-4-hydroxymethyl-5-aminomethylpyridine dihydrochlor-ide,

Similarly, 2-methyl-3-amino-4 beniyloxymetli- 4 6. A compound of the formula onion HaCKAI and hydrohalide salts thereof.

'7. The process that comprises reacting a compound of the formula wherein R is selected from the class consisting of .alkyl, aryl, and ara'lkyl groups with a hydrohalic yl 5 amino methylpyridine and 2-meth'y1- 3 amino-4-phenoxymethyl-5-aminomethylpyridine can be treated with other hydrohalic acids to obtain 2 methyl 3-amino+4-halogenmethyl-5- aminomethylpyridine.

The free bases corresponding to 2-methyl-3- amino-4-hydroxyrnethyl-5-aminomethylpyridine and 2-methyl-3-aminol-halogenmethyl-5-aminomethylpyridine are obtained by treating the acid salts with alkali, evaporating to dryness, and extracting with an organic solvent such as alco- 1101 I01" acetone.

Modifications may be made in carrying out the present invention without departing from the spirit and scope thereof and the invention is to be limited only by the "appended claims.

What is claimed is; p I

1. A compound of the formula:

wherein X is selected from the group consisting of halogen and hydroxyl; and salts thereof.

2. A compound of the formula:

' I'CH2X wherein 'X is halogen; and salts thereof.

3. A compound-of the formula:

carer HzN CHzNHz Ha C N and salts thereof.

4. A compound of the formula:

CH2QH CHZNHH and salts thereof.

5. A compound of the formula:

OHzBr v CHzNHg and hydrohalide salts thereof.

acid to ob'ta i'n'a hydrohalide of 2-methyl-3-amino 4 halogenmethyl S-aminomethylpyridine,

' and removing the hydrohalide to produce 2- -rnethyl-3-arnino 4 halogenmethyl 5 amino methyl-pyridine.

8. The process that comprises reacting a compound of the formula wherein R i-s'a-IRy'l with a hydroha-lic acid to obtain a hydrohalide of 2-methyl-3-amino-4-halogenmethyl-5-aminomethylpyridine, and removing the hydrohalide to produce 2-methyl-3-aminol-h'alogenmethyl 5-aminomethyl1oyridine.

9. The process that comprises reacting a-compound of the formula wherein R is aryl with aI-hydrohalic acid to obtain a hydrohal-ide of 2-methyl-3-amino-4-halogenmethyl-5-aminomethylpyridine, and remow ing the hydrohalide to produce 2-mtl'1y1-3- amino-4-halogenmethy1 5 aminornethylpyridine.

10. The process that comprises reacting-a, compound of the formula V wherein R is arallsyl with a hydrohalic acid to obtain a hydrohalide of 2-methyl-3-amino-4-halogenmethyl-B-aminomethylidyridine, and removing the hydrohalide to produce 2-'me'th'yl-3- amino-4 hailogenHrethyl-B-aminomethylpyridine.

11. The process. that comprises reacting 2- .methy'l-3-amino 4 ethoiq methyk 5 aminomethylpyridinewith ahydroha'licacid to obtain a hydroh'alide of 2-methyl-3eamino lhalogenmethyl-J5-aminomethylpyridine, and removing the hydrohalid'e to produce 2-methyl-3- amino-4- halogenmethyl-fieaminomethylpyridine.

"12. The: process .that comprises reacting 2- ylpyridine with hydrobromic'ac'id toobtain :a. hy-

' drohalide' of 2-mthyl- 3+arriinb 4=bromomethyh 5-annnbmethylpyridine, ,7 land removing the :hy- -drohalide to ;produce'2 methyl"-- *3 amino- 4- bromomethyl-5-aminomethylpyridine.

13. The process that comprises hydrolyzing a compound of the formula CHaOR HgN CHBNHt wherein R is selected from the class consisting of alkyl, aryl, and aralkyl groups to obtain the acid salt of 2-methyl-3-amino-4-hydroxymethyl- B-aminomethylpyridine, and treating this compound with alkali to obtain 2-methyl-3-amino- 4-hydroxymethyl-5-aminomethy1pyridine.

14. The process that comprises hydrolyzing a compound of the formula CHzOR HzN CHzNHz HaC wherein R is aryl to obtain the acid salt'of 2'- methyl 3 amino 4 hydroxymethyl-5-amin0- methylpyridine, and treating this compound with alkali to obtain 2-methyl-3-amino-4-hydroxymethyl-5-aminomethylpyridine.

16. The process that comprises hydrolyzing a compound of the formula V CHgOR wherein R is aralkyl to obtain the acid salt of 2- meth'yl-3-amino 4 hydroxymethyl 5 aminomethylpyridine, and treating this compound with alkali to obtain 2-methyl-3-amino-4-hydroxymethyl-5-aminomethylpyridine.

17. The process that comprises hydrolyzing 2- methyl 3 amino 4 ethoxymethyl 5 aminomethylpyridine to obtain the acid salt of Z-methyl-3-amino-4-hydroxymethyl 5 aminomethylpyridine, and treating this compound with alkali to obtain Z-methyl-B-amino-4-hydroxymethyl- 5-aminomethylpyridine.

18. The process that comprises treating 2- methyl 3 amino 4 ethoxymethyl 5 -aminomethylpyridine with hydrochloric acid to obtain the hydrochloride of 2-methyl-3-amino-4-hydroxymethyl-5-aminomethylpyridine, and treating this compound with alkali to obtain 2-meth'yl- 3-amino-4-hydroxymethyl 5 aminomethylpyridine.

STANTON A. HARRIS. 

